Cellulose Insulation
Cellulose insulation is made from recycled wood fibre, primarily newspaper. One hundred kilos of cellulose insulation contains 80 to 85 kilos of recycled newsprint, partly solving a major waste disposal problem for cities.
Cellulose maintains its U-value with humidity levels of up to 40%, other fibrous insulations lose their insulating effect substantially when humidity levels rise over 10%. Cellulose keeps your roof timbers healthy and dry giving them a long life. Cellulose insulation comply's with strict flammability and corrosiveness standards.
Cellulose has a higher Lambda value and tightens buildings better against air infiltration than Fiber glass or Rockwool insulation. A study by the University of Colorado School of Architecture and Planning found Cellulose to be at least 36% better than Fiberglass at Air tightening buildings. Cellulose is not subject to convective heat losses, which has been shown to reduce the Lambda value of Fiberglass insulation by 20 to 40% under Winter conditions. An Oak Ridge National Laboratory study showed the U-value of a Fiberglass installation drop from 0.25W/m2.K to 0.325W/m2.K when the temperature dropped to -10 degrees C.
Cellulose Insulation requires much less energy to produce than Mineral wool, which is made in gas-fired furnaces. According to some estimates it takes from 20 to 200 times more energy to make Mineral wool than to produce an equivalent amount of Cellulose.
When Cellulose is installed at a density of 60kgs or more it gives a Decrement Delay of 11 hours, substantillly slowing down heatloss, even more than the U-value suggests.
Comparing Cellulose Insulation with Rockwool. Left below, a hair dryer blows air into the box. The left compartment is filled with Cellulose, and the right compartment is filled with Rockwool.
On the right, the air blows through the Mineral-wool and lifts up the tennis ball up to the top of the tube, the ball over the Cellulose stays down. One clear message from the experiment: When you use Cellulose you get a better blower-door test and suffer less heatloss due to the convections in fibrous insulations at lower temperatures.
Passive House wall in Sweden insulated with Cellulose